• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2182-2189
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• 2024

The high-purity germanium gamma-ray spectrometer was used to measure the radioisotope in surface water of lakes in a Chinee petroleum industrial area. 92 samples were collected from surface water of three lakes. Activity concentrations of ²³²Th, ²²⁶Ra and ⁴⁰K in three lakes were measured, distributed in the range of 101.8-209.4, 192.1-224.9 and 335.0-548.9 mBq/L, respectively. Results were all within the limits of WHO and China. Potential environmental and health risks were assessed by calculating some radiation hazard indicators, radium equivalent index, annual effective dose, excess lifetime cancer risk, absorbed dose rate, external hazard index, internal hazard index, annual gonadal dose equivalent, activity utilization index and representative gamma index, which ranged 0.38-0.54 Bq/L, 0.06-0.08 mSv/y, 0.23 × 10^-3-0.31 × 10^-3, 0.17-0.24 nGy/h, 1.01 × 10^-3-1.46 × 10^-3, 1.55 × 10^-3-2.02 × 10^-3, 1.16-1.66 μSv/y, 3.13 × 10^-3-4.45 × 10^-3 and 2.60 × 10^-3-3.77 × 10^-3. The results were all at acceptable levels, meaning no impact on human health. The relationship between the electrical conductivity of surface water and the activity concentration of ²³²Th, ²²⁶Ra and ⁴⁰K was evaluated. The electrical conductivity value was 0.241-0.369 mS/cm, showing a significant correlation coefficient between ²²⁶Ra and ⁴⁰K and electrical conductivity. Multivariate statistical methods were used to determine the relationship between the activity concentrations of ²³²Th, ²²⁶Ra, and ⁴⁰K, radiation hazard indicators and electrical conductivity.

• The Journal of Society for e-Business Studies
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• v.15 no.4
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• pp.143-163
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• 2010

The purpose of this study is to investigate the user's perception of security risk and examine its impact on the usage of Knowledge Management Systems(KMS). The findings of this study are three-fold. First, the overall user's perception of security risk is not high. However, there is a considerably big difference in the perception of security risk among users. This finding means that user's perception of a security risk is not based on the actual security effects but one's individual perception. Another finding is that user's perception of a security risk has a negative impact on the usage of KMS through "trust", which is a mediating variable in our study. This finding corresponds with the existing theory that security risk is oneof the critical sources of trust, and trust is a critical factor of user's acceptance of KMS. Finally, the result of this study reveals that activities devoted to security do not decrease the effectiveness and productivity of KMS. Our long-held cognition that security activity hinders the effectiveness and productivity of an information system is not particularly applied to the KMS.

• Journal of Distribution Science
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• v.12 no.8
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• pp.113-121
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• 2014

Purpose - Recently, the number of corporations that practice environmental and social responsibility, besides engaging in traditional profit-seeking activities, has been growing steadily, as interest in Corporate Social Responsibility (CSR) is increasing. Recent research on CSR practices has identified the relationship between CSR activities and corporate value as one of the main issues in this respect. Considering that donations constitute a large proportion of a company's charitable activities, we considered the extent of donation expenses as a charitable activity in order to mitigate sample selection bias. Specifically, we analyzed the impact of donation expenses on firm value, while investigating if this impact varied in response to the level of corporate governance of firms. Research design, data, and methodology - We used non-financial firms listed on the Korean Stock Exchange, having their fiscal year end in December, and the sample period was 2006-2013. For the dependent variable, Tobin's q was used as the corporate value, and for the independent variable, donations were measured as the donation-expense-to-sales ratio. Corporate governance scores, as rated by the Korea Corporate Governance Service, were used to measure corporate governance levels because they consider the overall aspects of governance, including ownership structure, the board of directors, and the audit mechanism of individual companies. To examine the impact of donations on a company in relation to the level of corporate governance, we estimated regression models using the interaction terms of the governance dummy and donation variables. Then, we further estimated the regression models of two sub-samples that were classified according to the level of corporate governance. Similar to previous studies, the study uses variables that affect firm value, such as R&D expenditure, advertising expenses, EBITDA, debt-to-equity ratio, sales growth, company age, and company size as control variables. Results - The empirical results show that firm value significantly increased in response to an increase in donation expenses. Upon including the interaction terms of governance level dummy variables and donations, the coefficients of the interaction terms show significant positive values, while those of donation variables show significant negative values. In the strong governance sub-sample, the relationship between the donation expenses and corporate value was statistically positive (+) and significant. However, in the weak governance sub-sample, the relationship between the donation expenses and corporate value was statistically insignificant and negative (-). Conclusions - The empirical results suggest that donation expenses are significantly linked to an enhanced corporate value if firms have a good corporate governance structure. However, if the corporate governance structure is weak, the same relationship is not necessarily observed. The results of this study show that if a firm has high corporate governance, CSR practices enhance the company's reputation such that it has a positive (+) relationship with corporate value. If a firm has weak corporate governance, on the other hand, CSR practices are recognized as an agency cost and do not increase corporate value.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.911-917
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• 2011

This study was to investigate the characteristics of the Yakju fermented with differently-processed lotus leaves such as blanching, steaming, roasting, and drying, and fresh one for control. The total acid content was high (0.82~1.22%) in the lotus leaf Yakju, and lactic acid was the main compound among organic acids. Volatile acid content was high (200~500 mg/L) compared to the results of organic acid composition, and the main volatile acid in lotus leaf Yakju was acetic acid. Though the polyphenol content (616.5~693.1 mg/L) was similar among the Yakju, the Hunter's color value of those were quite different and also had a big impact on the sensory evaluation of color. Therefore, it seems that the enzyme activity of polyphenol oxidase in differently-processed lotus leaves may have an influence on the color of lotus leaf Yakju. In a sensory evaluation of color and aroma, lotus leaf Yakju fermentaed with fresh leaves and roasted ones were preferred to the others, and steamed leaves and roasted ones were the best in taste and overall acceptability.

• Ocean and Polar Research
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• v.30 no.3
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• pp.289-301
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• 2008

Community structure of heterotrophic protists and their grazing impact on phytoplankton were studied in Northwest Pacific Ocean during October, 2007. The study area was divided into four regions based on physical properties (temperature and salinity) and chlorophyll-a distribution. They were Region I of North Equatorial Currents, Region II of Kuroshio waters, Region III of shelf mixed water, and Region IV of Tsushima warm current from East China Sea. The distribution of chlorophyll-a concentrations and community structure of heterotrophic protists were significantly affected by physical properties of the water column. The lowest concentration of chlorophyll-a was identified in Region I and II, where pico-sized chlorophyll-a was most dominant (>80% of total chlorophyll-a). Biomass of heterotrophic protists was also low in Region I and II. However, Region III was characterized by low salinity and temperature and high chlorophyll-a concentration, with relatively lower pico-sized chlorophyll-a dominance. The Highest biomass of heterotrophic protists appeared in Region III, along with the relatively less important nanoprotists. In Region I, II and IV, heterotrophic dinoflagellates were dominant among the protists, while ciliates were dominant in Region III. Community structure varied with physical(salinity and temperature) and biological (chlorophyll-a) properties. Biomass of heterotrophic protists correlated well with chlorophyll-a concentration in the study area ($r^2=0.66$, p<0.0001). The potential effect of grazing activity on phytoplankton is relatively high in Region I and II. Our result suggest that biomass and size structure of heterotrophic protists might be significantly influenced by phytoplankton size and concentration.

• Journal of Environmental Science International
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• v.25 no.9
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• pp.1329-1339
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• 2016

The purpose of this study was to obtain the basic data needed to identify the impact of the odor, emitted from the Ochang Scientific Industrial Complex area on the surrounding residential areas by measuring and confirming odor compounds. The analysis showed that complex odors were diluted from around 4 to 1. The offensive odor measurement results showed that among the sites, site 1 was highest in sulfur compounds, site 2 was highest in toluene, site 3 was highest in trimethylamine, and site 4 was highest in buthylaldehyde. It cannot be decided to be odor-causing compounds for higher odor concentration because each odor substance has a different odor threshold value. According to the odor contribution analysis for each site, site 1, site 2, and site 4 contained high buthylaldehyde concentrations, and site 3 had a high level of trimethylamine. It could be determined that highly evaluated substances were main causes to result in substance for each site.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.3
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• pp.161-168
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• 2011

Purpose: The odontogenic keratocysts demonstrated a high recurrence rate and a biologically aggressive nature. This might be due to unknown factors inherent in the epithelium or enzymatic activity in the fibrous wall. Bcl-2 protein is characterized by its ability to inhibit apoptosis. The aim of this study was to evaluate the expression and distribution of bcl-2 in the OKCs, its possible relationship with the tumorous characteristics, such as the aggressive nature and high recurrence rate, and its usefulness to differentiate OKCs from dentigerous cysts. Materials and Methods: Formalin fixed paraffin-embedded tissue sections of 53 OKCs, and 44 dentigerous cyst were immunohistochemically analyzed quantitatively for the immunoreactivity of the bcl-2 protein with i-solution. Results: More Bcl-2 expression was observed in the OKCs (mean34.387%) than dentigerous cyst (mean11.144%) with statistical significance (P<0.001). Seventeen and 15 of the 32 OKCs in this study showed positivity in the basal layer and basal/suprabasal layers, respectively. In dentigerous cyst, 2 of 3 showed positivity in the basal cell layer. Conclusion: Considering that bcl-2 over expression may lead to the increased survival of epithelial cells, this study demonstrated a possible relationship between the aggressive nature of OKC and the intrinsic growth potential of its lining epithelium. Furthermore, the basal/suprabasal distribution of bcl-2 positive cells was observed in some OKCs, which might have a significant impact on the behavior of cysts. The bcl-2 expression of OKCs can be useful for differentiating OKCs from dentigerous cysts.

• PNF and Movement
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• v.10 no.1
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• pp.9-17
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• 2012

Purpose : This study's purpose is consideration about change of the hand grip strength according to different posture and shoulder flexion angle. The shoulder joint permits the greatest mobility and carries out the important function of stabilization for hand use. Hand grip activity is important to evaluate while assessing loads of shoulder in hand mobilities. Methods : Thirty(15 male, 15 female) college students with unknown shoulder dysfunction participated subject in five different positions of elbow extension with sitting and standing posture, different positions is followed : (1) shoulder $0^{\circ}$ flexion (2) shoulder $45^{\circ}$ flexion (3) shoulder $90^{\circ}$ flexion (4) shoulder $135^{\circ}$ flexion (5) shoulder $180^{\circ}$ flexion. Results : On the average, in the hand grip strength, the standing posture is higher than sitting posture. Sitting posture showed a most high level at the man's $0^{\circ}$ and woman's $135^{\circ}$. And standing posture showed a most high level at the man's $135^{\circ}$ and woman's $90^{\circ}$. Conclusion : The paired t-test was used to determine the different in grip strength between sitting and standing posture by shoulder angle change. There was no significant difference between the five position by sitting and standing posture. In man, correlation analysis revealed significant connection for all five position by sitting and standing posture. And in woman, correlation analysis revealed connection for all five position by sitting and standing posture.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.291-304
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• 2023

Harmful algal blooms (HABs) have become an increasing concern in terms of human health risks as well as aesthetic impairment due to their toxicity. The reduction of water pollutants, especially nutrients from non-point sources in a reservoir watershed, is fundamental for HABs prevention. We investigated the pollutant removal efficiencies of a constructed wetland to evaluate its feasibility as a method for controlling non-point sources located in the Annaecheon stream within the Daecheong Reservoir watershed. The overall removal efficiencies of pollutants were as follows: BOD 14.3%, COD 17.9%, SS 50.0%, T-N 19.0%, and T-P 35.4%. These results indicate that constructed wetlands are effective in controlling pollutants from non-point sources. The seasonal variation in removal efficiency depended on the specific pollutants. The removal efficiencies of BOD, COD, and T-N were stable throughout the year, except during winter, which might have been influenced by lower microorganism activity. In contrast, T-P showed a consistent removal efficiency even during the winter season, suggesting that the wetland can reduce external phosphorus loading to the reservoir. Regarding the effects of pollutant loadings on removal efficiency, the effluent concentrations of all pollutants were significantly decreased compared to those in the influent in case of middle and high loadings. This demonstrates that constructed wetlands can handle high pollutant loads, including the initial runoff during rainfall, to prevent reservoir eutrophication. Despite the various strengths of wetland water purification, there are limitations as passive treatment. Therefore, more case studies should be conducted to suggest optimum operational conditions for constructed wetlands, taking into consideration reservoir-specific characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.12
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• pp.1695-1699
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• 2004

The antioxidant enzymes, lipid peroxidation and free radicals assessment were made of the effects of selenium, copper and magnesium on bovine endemic fluorosis under high fluoride, low selenium and low copper productive conditions. Thirty-two beef cattle were selected from high fluoride area, and randomly divided into four groups with eight cattle each as follows: (1) high fluoride control group (HFC); (2) supplemented group with 0.25 mg/kg selenium (HFSe); (3) supplemented group with 15 mg/kg copper (HFCu) and (4) supplemented group with 0.25 mg/kg selenium+15 mg/kg copper+1 mg/kg magnesium (HFSeCuMg) per day for 83 days. Moreover, eight beef cattle were selected from non-high fluoride area as normal control group. Blood samples were collected from cattle on 0 d, 30 d and 83 d respectively, to analyze the enzyme activities and concentration of GSH-px, CAT, SOD, MDA and free radicals. The results showed that the contents of free radicals and MDA in HFC group were significantly higher, and the whole blood GSH-px, CAT, erythrocyte SOD activities were lower than the normal control group. Free radicals, metabolic imbalance and antioxidant disorder therefore, play an important role in fluorosis. However, GSH-px, CAT and SOD activities in HFSe group and HFSeCuMg group at 30 d and 83 d were markedly higher than the same groups at the 0 d and the HFC group at the same time. Likewise, there was a corresponding reduction in the contents of free radicals and MDA. These findings indicated that supplementation with selenium, copper and magnesium elevated high fluoride bovine antioxidant enzymes, and decreased MDA and free radicals contents. But, the activities of supplementation selenium group did not increase until day 83. These results demonstrated that fluorosis was associated with lower serum Se and Cu levels than in the control, and it was therefore concluded that fluorosis is associated with decreased serum levels of these minerals. Long-term high fluoride intake under productive condition enhances oxidative stress in the blood, thereby disturbing the antioxidant defense of cattle. Increased oxidative stress could be one of the mediating factors in the pathogenesis of toxic manifestations of fluoride. It is benefical for high fluoride cattle supplemented with proper selenium, copper and magnesium to increase fluoride excretion and obtain the protective impact of the activity of oxidative enzymes, and to decrease lipid peroxidation and free radicals contents.